Apparatus for forming strand assemblies



Jan. 28, 1941.

- Filed July 1, 1938 4 4. a 0 [HM 5 x a "mm v 9 4 4 .II M 4 7 n m a a M, 0m P T/ 0 mx w 5 A i .H

atented Jan. 28, 1941 ,zzatez APPARATUSAFOR FR. il'il:

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Application July 1, 1938, Serial No. 216,8%

2 Claims.

This invention relates to an apparatus for forming a covered strand assembly, and more particularly to an apparatus for forming insulated electrical conductors.

In some of the many instances where insulated electrical conductors are employed the conductors are subjected to various treatments or tests, such as twisting and bending, and it is usually important that the bare conductors do not project through the insulation during such treatments.

Objects of the invention are to provide a simple, emcient and practical apparatus for forming a strand assembly.

With these and other objects in View, the invention comprises an apparatus for forming a strand assembly formed by the apparatus shown in Fig. 1.

In the present embodiment of the invention a a selected number of strands i0 is fed to a strand twisting unit I i Although six strands are shown in the present instance, it should be understood that any desired number of strands may be selected. The strands i0 are guided over a plurality of sheaves I2, rotatably carried by the twisting unit H, to guide the strands to a twist-' ing point it where they are twisted together during their advancement while the unit it is rotated through a pulley it operatively connected to suitable drive means (not shown). The strands are advanced at a suitable speed by any desired means (not shown) such as a capstan. and during advancement the strands pass from the twisting point 13 through a tubular member l6, which is part of the unit It and .upon which the pulley it is mounted. The twisted ostrands, upon leaving the unit H, pass over sheaves l8 and i9 and are directed downwardly through a tubular guide 2| of a knitting unit 22. The guide 2| is carried by cross bar 23 supported by uprights 25 (only one of which is shown in the drawing), the latter being mounted upon a base 25 which also serves as a support for the knitting unit 22. A bracket 26 adjustably secured to one of the uprights it has vertically extending pins 27 to rotatably support on the bracket a plurality of tension discs 28. Strands or threads 29 of suitable material such as textile cotton are fed around the tension discs 28 from suitable supply means (not shown). A plurality of thread guides 33 in the form of pins with apertures in the ends thereof through which the 1 threads may pass are adjustably secured in spaced apertures in an annular supporting member 36, the latter being adjustably mounted upon the tubular guide 29.

Another knitting unit t2, having a tubular guide 6! positioned thereabove and supported by a cross bar 33 mounted upon uprights M1, is supported by a base 35 upon which the uprights it are also mounted. A bracket it, having pins til, rotatably supports sheaves d8 around which strands or threads is are directed from suitable supplies (not shown). The threads 59 pass through apertures in the ends of thread guides 53 which are adjustably mounted in apertures of an annular supporting member 5d, the latter being adjustably mounted upon tubular guide 6!.

The detailed construction of the knitting units is not shown in the drawing nor described in the specification, these units being shown and described in detail in Patent No. 2,126,250, issued August 9, 1938, to Ben K. Ford.

To illustrate the present embodiment of the invention the twisting unit i i is rotated counterclockwise, looking from the top, thus twisting the strands together to form a core. The strands 2 thus twisted are advanced to the knitting unit 22 where, at point 56, a knitted cover is formed upon the twisted strands. The knitting units shown are of the type which form interconnected loops on the outside of the needle carrier, the loops while being formed extending in the direction of rotation of the needle carrier, but when pulled over the top of the needle carrier and onto the twisted strands their positions are reversed and they extend spirally in a direction opposite the direction of rotation of the needle carrier These interconnected loops of successive threads are commonly known as wales. The needle carrier 51 of the knitting unit 22 is, therefore, rotated clockwise, looking from the top, causing the knitted cover to be formed on the strands with the wales thereof extending in the same direction as the twist of the strands. This knitted cover is indicated at 58 in Fig. 2, which figure illustrates the twist in the strands and 55 the wales in the cover 58 as being in the same direction.

The twisted strands with the cover 58 are'advenced to the knitting unit 42 where, at point 59, a second cover is formed. This second cover is knitted over the first cover but the wales therecover 58. However, the courses, which include the float bars of the respective threads, extend longitudinally of the axis of the core consisting of the intertwisted strands.

When the finished insulated strand assembly shown in Fig. 2 is twisted in either direction the knitted loops of one cover might tend to loosen but the twist would tighten the knitted loops of the other cover. For example, let it be assumed that the assembly was given a twist in a direction which would tend to loosen the strands. Such a twist would tend to loosen the cover 58 but would effect a tightening of the cover 6!, thus preventing any of the strands from passing through the covers and becoming exposed. A twist of the strand assembly in the opposite direction would tend to loosen the cover 6| but such a twist would-tighten the strands, bringing them closer together, if possible, and at the same time tighten the cover 58 upon the strands. When the strand assembly is bent the portions of the covers adjacent the inner arc of the bend will tend to loosen but the portions adjacent the outer arc thereof will tighten, thus eliminating any possibility of the strands becoming exposedr It is, therefore, possible for the strand assembly to be subjected to the usual twisting and bending without danger of the conductor strands being exposed through the insulating covers.

It should be understood that the covers may be' applied toumtwisted strands, that the directions of twist in the strands and the directions of the applications of the knitted covers may be varied, that the covers may be formed with the courses extending spirally in transverse directions about the core and the wales extending longitudinally of the core, and that the embodiment of the invention herein disclosed and illustrated may be otherwise modified and departed ,from in many ways without departing from the spirit and scope of the invention, as pointed out in and limited only by the appended claims.

What is claimed is:

1. In an apparatus for forming strand assemblies, means to intertwist electrical conductor strands in one direction, and separate means to knit successive covers on the twisted strands with the wales of one cover extending substantially in the same direction as the direction of twist of the strands and transverse to the direction of the wales of another cover.

2. In an apparatus for forming strand assemblies, means to intertwist electrical conductor strands in one direction, means to knit a cover on the twisted strands with the wales of the cover extending substantially in the same direction as the direction of twist of the strand, and means to knit a second cover on the first cover with the wales of the second cover extending in a direction transverse to the direction of the wales of the first cover.

HENRY R. MASSINGHAM. 

